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Clamp the tracking factors to avoid blowups

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This commit is contained in:
Paul Ferrand 2020-08-21 11:36:09 +02:00
parent afc9d72c89
commit dd8134277c
2 changed files with 16 additions and 2 deletions
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12
src/sfizz/Voice.cpp
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@ -237,6 +237,14 @@ void sfz::Voice::registerTempo(int delay, float secondsPerQuarter) noexcept
UNUSED(secondsPerQuarter); UNUSED(secondsPerQuarter);
} }
void sfz::Voice::updateTrackingFactor() noexcept
{
// Protect the envelope follower against blowups
const auto maxTrackingFactor = sampleRate / samplesPerBlock;
attackTrackingFactor = min(config::powerFollowerAttackFactor, maxTrackingFactor) / sampleRate;
releaseTrackingFactor = min(config::powerFollowerReleaseFactor, maxTrackingFactor) / sampleRate;
}
void sfz::Voice::setSampleRate(float sampleRate) noexcept void sfz::Voice::setSampleRate(float sampleRate) noexcept
{ {
this->sampleRate = sampleRate; this->sampleRate = sampleRate;
@ -249,13 +257,13 @@ void sfz::Voice::setSampleRate(float sampleRate) noexcept
for (auto& lfo : lfos) for (auto& lfo : lfos)
lfo->setSampleRate(sampleRate); lfo->setSampleRate(sampleRate);
attackTrackingFactor = config::powerFollowerAttackFactor / sampleRate; updateTrackingFactor();
releaseTrackingFactor = config::powerFollowerReleaseFactor / sampleRate;
} }
void sfz::Voice::setSamplesPerBlock(int samplesPerBlock) noexcept void sfz::Voice::setSamplesPerBlock(int samplesPerBlock) noexcept
{ {
this->samplesPerBlock = samplesPerBlock; this->samplesPerBlock = samplesPerBlock;
updateTrackingFactor();
} }
void sfz::Voice::renderBlock(AudioSpan<float> buffer) noexcept void sfz::Voice::renderBlock(AudioSpan<float> buffer) noexcept

6
src/sfizz/Voice.h
View file

@ -485,6 +485,12 @@ private:
Smoother xfadeSmoother; Smoother xfadeSmoother;
void resetSmoothers() noexcept; void resetSmoothers() noexcept;
/**
* @brief Update and clamp the tracking factors to ensure the power
* follower does not blow up.
*
*/
void updateTrackingFactor() noexcept;
float attackTrackingFactor { config::powerFollowerAttackFactor / config::defaultSampleRate }; float attackTrackingFactor { config::powerFollowerAttackFactor / config::defaultSampleRate };
float releaseTrackingFactor { config::powerFollowerReleaseFactor / config::defaultSampleRate }; float releaseTrackingFactor { config::powerFollowerReleaseFactor / config::defaultSampleRate };
float meanChannelPower; float meanChannelPower;